The invention concerns a rotary-ring carriage for a light weapon on a combat vehicle, especially for hatchway of a military tank. The weapon is mounted on an undercarriage. The undercarriage rolls on wheels along curved rails.
Carriages of this type are in themselves known. The rails are continuous rings, and the undercarriage can roll unimpeded 360.degree. and more, covering the complete azimuth. When such a carriage is mounted at a conventional hatchway, which has a folding hatch, gaps in the rails are usually filled in with sections mounted on the hatch, ensuring continuous arcs.
Military tanks are known (from German OS 3 305 882) with a hatchway at the top of the chassis or turret and with a hatch comprising two components of different mass. One is positioned above the other at least when the hatchway is closed. The upper and heavier component is positioned above the upper edge of the hatchway and slides back and forth parallel with the hatch's plane of closure. The other and lighter component can be mounted on the bottom of the upper component and move perpendicular to the plane of closure. The hatch components operate in conjunction to seal off the hatchway.
It is in some situations extremely difficult to provide such hatches with rails in the form of continuous arcs. The same problem can occur with folding hatches when they have heavy counterweights.